The Mercury shift-rod o-ring #25-85594, passed the pressure test with flying colors.
My homemade test device leaked where I screwed it into the gearcase oil overflow, probably because I didn’t want to waste a proper plug washer/gasket.
I repeatedly tested with soapy water applied to all seals and screws at 7-10 psi. I also vacuum tested.
Lastly, I submerged the unit in water. The gage needle didn’t budge, and no air bubbles emerged even when I repeatedly moved the shift rod up and down.
I’m calling it a win.
1956 Johnson 15 Hp, FD-10
1957 Johnson 5.5 Hp, CD-14
1958 Johnson 5.5 Hp, CD-15
